摘要
用滚筛机(6CXF-70大宗茶鲜叶分级机,MCF自制名优茶鲜叶分级机),平面圆筛机(浙茶精766)、风选机(FX450型)等不同茶叶分级机械对相同机采鲜叶原料进行分级,鲜叶原料在不同筛孔、风力条件下,按芽叶大小、轻重归类,实现大小芽叶分离,测定经分级后得到的各类芽叶机械组成,比较分级效果。结果表明:试验用机器采摘的茶青机械组成中标准芽叶的比例(质量分数,下同)为23.54%,粗老芽叶的比例为43.33%,其他碎片的比例达到33.13%。该鲜叶不能作为名优茶生产。经滚筛机分级,在相同分级区段内,MCF分级机分级获得的标准芽叶比率较6CXF-70大宗茶鲜叶分级机高19%,且各筛孔下得到的原料等级界限清楚。利用不同筛孔分层设置的平面圆筛机分级原料,各层级中均有标准芽叶和其他芽叶混杂的情况,不能较好地分离出鲜叶中的标准芽叶。风选机分级能较好地清除机采鲜叶内其他碎片,但标准芽叶和粗老芽叶分离效果不明显;MCF和风选组合分级效果提高。机采鲜叶先经MCF分级,再风选处理,标准芽叶比例提高了16%,其他碎片比例下降了23%,从而有效地减少了标准芽叶和其他碎片混杂。然而先风选再MCF组合分级,分级效果不理想;但是调整自制分级机结构可在一定程度上获得等级差异明显的芽叶。综上,利用滚筛、平面圆筛、风选等方法可以使机采鲜叶原料在一定程度上按大小归类,不同方法分级差异大,其中滚筛分级是3种分级方法中可获得相对整齐、标准芽叶较多的分级方法,利用自制的名优茶鲜叶分级机(MCF)与风选组合分级效果最优。
Although the harvesting of fresh, high quality tea leaves has traditionally relied on hand-plucking, labor shortages and the rise in the cost of hand-plucking have restricted the growth of quality tea production and the development of the tea industry. This problem would he effectively resolved if the fresh tea leaves harvested through machine plucking could be used for the production of high quality tea. However, few studies to date have been reported in this respect. Based on current machine-plucking technolog'y, fresh tea leaves are difficult to harvest, as the raw material, consisting of mixed shoots and leaves, varies in size and tenderness. In order to meet the production standards of high quality tea, machine-plucking technology must be improved. This study aims to explore the technological development of the machine-plucking classification method of fresh tea leaves. Three methods of classification of fresh, machine-plucked tea leaves were compared in this study: 1) roll screen (6CXF-70 bulk tea leaves classification machine, MCF selbmade high quality tea leaves classification machine) ; 2) flat circular screen (Zhechajing 766) ; and, 3) wind election (FX450 type). The raw material was classified by size and mass in varying sieve and wind condition. In addition, the mechanical compositions of classified fresh tea leaves were also analyzed to compare the classification effects. Among the fresh, machine-plucked tea leaves, which were not suitable for the manufacture of high quality tea, the 23.54% were standard shoots, 43. 33% were coarse old shoots and 33.13% were other debris. The results of the roll screen method showed that the proportion of standard shoots classified by MCF was 19% higher than those classified by 6CXF-70 within the same classification range. The flat circular screen was unable to adequately separate shoots by size. The wind election method was more effective at removing debris, but it was not able to separate fresh, standard shoots from old, coarse shoots. The classification effect was vastly improved by combining the MCF and wind election methods. When the fresh, machine-plucked tea leaves were first classified by MCF and then by wind election, the proportion of standard shoots to coarse shoots rose by 16%, and the debris decreased by 23%. This result indicates that the MCF in combination with the wind election method is effective in separating standard shoots from debris. The classification effect, however, was not observed if the order of methodology was reversed. These results clearly indicate that adjusting the structure of classification mechanisms can result in greater separation of standard shoots to a certain extent. Although the three classification methods of roll screen, flat circular screen, and wind election all have the ability to separate fresh tea leaves by size, each method varies in effect. In conclusion, the roll screen method of classification results in more precise and standardized shoots, and the classification effect is most pronounced by combining the methods of MCF and wind election.
出处
《浙江大学学报(农业与生命科学版)》
CAS
CSCD
北大核心
2012年第5期593-598,共6页
Journal of Zhejiang University:Agriculture and Life Sciences
基金
浙江省科技厅"名优茶机采原料分级技术研究"(2011C22081)
苍南县科技局"名优茶鲜叶原料分级机(MCF)研究"(2009N29)
关键词
茶
鲜叶
机采
分级
筛分
风选
tea
fresh leaves
machine-plucking
classification
screening
wind election